In reciprocating engines, a piston reciprocates within a cylinder. The piston is connected to a crankshaft by a connecting rod such that movement of the piston drives the crankshaft. A bearing is provided between the connecting rod and the crankshaft to absorb radial forces generated by the relative movement between the connecting rod and the crankshaft. The axial ends of the bearing contact a surface of the crankshaft. Often, the axial ends of the bearing are flanges that extend radially outwardly from opposing ends of the bearing's cage such that they are disposed between opposing surfaces of the connecting rod and crankshaft. The contact between the connecting rod faces and the crankshaft can cause the interface surface to wear poorly. Also, the friction generated between the connecting rod and the bearing and between the crankshaft and the connecting rod generates heat that can cause damage to the bearing or the components themselves.
The prior art includes various attempts designed to decrease the amount of friction generated between the connecting rod and the crankshaft, for example, lubrication of the connecting rod and crankshaft interface, such as by spray lubrication. However, the gaps that exist between the connecting rod and portion of the crankshaft to which it is connected are typically reduced due to the radial flanges of the bearing's cage which extend outwardly into those gaps. Moreover, tight tolerances can hinder the ability to provide lubrication to the crankshaft's raceway on which the roller elements of the bearing ride.
The present invention recognizes and addresses considerations of prior art constructions and methods.